The invention relates to an apparatus for internally grinding rotationally-symmetrical workpieces, which are clamped in position in a grinding machine so as to be rotatable about their longitudinal axis, the apparatus having a grinding disc which is displaceable longitudinally of the rotational axis of the workpiece and is radially feedable according to the internal profile to be ground.
When rotating bodies are internally ground, it is usual practice to utilize grinding discs with a ratio of diameter to length of &gt;0.3. A grinding disc according to German Offenlegungsschrift No. 2 410 805 and German Offenlegungsschrift No. 2 336 705 has the disadvantage that it actually reduces the whole extent of grinding with its inclined end face when it passes once through the workpiece, but it is simultaneously the caliber for the finished dimension of the bore. In such a case, there is linear contact continuously between the bore face and the surface of the cylindrical portion of the grinding disc, with the result that the coolant does not act in its optimum manner. In order to keep the heating of the workpiece within limits, the operation is generally carried out at relatively low cutting speeds. In consequence, the operation takes a relatively long time, thereby increasing the workpiece costs accordingly. Moreover, the known grinding discs have to be trimmed whenever a workpiece is changed.
Furthermore, it is known from German Patent Specification No. 3 435 313 to effect enternal grinding of rotationally-symmetrical workpieces with a spindle which is mounted in an offset manner. However, the process described there cannot be readily applied to internal grinding because, firstly, in the case of the latter method the space available for the grinding disc when machining the bore is limited and, secondly, when the grinding spindle is solely disposed in an offset manner relative to the longitudinal axis of the workpiece, the disc does not have the desired grinding effect.